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Remediation of polycyclic aromatic hydrocarbon (PAH) contamination in soil remains expensive and difficult. Sulfate radical advanced oxidation processes (SR-AOPs) can be used for in situ PAH oxidation but their efficiency and ecological impacts require evaluation. Here, we tested the remediation efficiency and ecological impacts of an SR-AOP combining sodium persulfate and ferrous sulfate (FS), the FS SR-AOP with the chelating agent citric acid (FS+CA), and the FS SR-AOP with chelating agent and the surfactant IGEPALCA-720 (FS+CA+IG) compared with natural attenuation (control, CK). We measured PAH, soil physicochemical properties (pH, soil organic matter [SOM]), and soil biological properties (polyphenol oxidase [PPO] activity, peroxidase [POD] activity, soil microbes) in contaminated soil samples after incubation with FS, FS+CA, FA+CA+IG, or CK for 1, 15, and 30 d. Compared with CK, all SR-AOPs significantly decreased PAH after 1 d, with FS+CA+IG showing the highest efficiency (80.8%) and PAH removal peaking at 15 d. FS+CA+IG treatment reduced SOM the least and soil pH the most; after 30 d, SOM recovered to ~80% of the level observed in CK, but soil pH decreased further. PPO and POD activities were highest after 15 and 30 d of FS+CA+IG treatment. Real-time quantitative PCR demonstrated that SR-AOPs significantly decreased quantities of PAH-degrading bacteria, soil bacteria, fungi, and actinobacteria at 1 d, but after 30 d, the microbes recovered to levels similar to those observed in CK, with no significant differences among SR-AOPs. SR-AOPs reduced bacterial diversity and changed the dominant phylum from Acidobacteria to Firmicutes. In summary, SR-AOP treatment with both the chelating agent and the surfactant produced the best PAH removal and least SOM destruction but the largest pH decrease, although some factors recovered with longer incubation. This study provides key information for improving PAH remediation and evaluating its ecological impact., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

We designed a functional drug delivery system based solely on DNA. The whole system was built with only four DNA strands. Cyclization of DNA strands excluded the formation of byproducts. DNA aptamers were equipped to endow triangular DNA nanostructures with targeting ability. The homogeneity of materials enabled not only facile construction but also convenient loading of nucleic acid-based drugs with much ease.

Cancer immunotherapy has risen as a promising method in clinical practice for cancer treatment and DNA-based immune intervention materials, along with DNA nanotechnology, have obtained increasing importance in this field. In this review, various immunostimulating DNA materials are introduced and the mechanisms via which they exerted an immune effect are explained. Then, representative examples in which DNA is used as the leading component for anticancer applications through immune stimulation are provided and their efficacy is evaluated. Finally, the challenges for those materials in clinical applications are discussed and suggestions for possible further research directions are also put forward., (© 2021 Wiley-VCH GmbH.)

Polyaniline (PANI) is a promising cathode material for Zn-ion batteries (ZIBs) due to its intrinsic conductivity and redox activity; however, the achievements of PANI in high-performance ZIBs are largely hindered by its instability during the repeated charge/discharge. Taking advantage of the high conductivity, flexibility, and grafting ability together, a surface-engineered Ti 3 C 2 T x MXene is designed as a silver bullet to fight against the deprotonation and swelling/shrinking issues occurring in the redox process of PANI, which are the origins of its instability. Specifically, the sulfonic-group-grafted Ti 3 C 2 T x (S-Ti 3 C 2 T x ) continuously provides protons to improve the protonation degree of PANI and maintains the polymer backbone at a locally low pH, which effectively inhibits deprotonation and brings high redox activity along with good reversibility. Meanwhile, the conductive and flexible natures of S-Ti 3 C 2 T x assist the fast redox reaction of PANI and concurrently buffer its corresponding swelling/shrinking. Therefore, the S-Ti 3 C 2 T x -enhanced PANI cathode simultaneously achieves a high discharge capacity of 262 mAh g -1 at 0.5 A g -1 , a superior rate capability of 160 mAh g -1 at 15 A g -1 , and a good cyclability over 5000 cycles with 100% coulombic efficiency. This work enlightens the development of versatile MXene via surface engineering for advanced batteries.

Platinum-based anticancer drugs are a class of widely used agents in clinical cancer treatment. However, their efficacy was greatly limited by their severe side effects and the arising drug resistance. The selective activation of inert platinum-based drugs in the tumor site by light irradiation is able to reduce side effects, and the novel mechanism of action of photoactivatable platinum drugs might also conquer the resistance. In this review, the recent advances in the design of photoactivatable platinum-based drugs were summarized. The complexes are classified according to their mode of action, including photoreduction, photo-uncaging, and photodissociation. The rationale of drug design, dark stability, photoactivation process, cytotoxicity, and mechanism of action of typical photoactivatable platinum drugs were reviewed. Finally, the challenges and opportunities for designing more potent photoactivatable platinum drugs were discussed.

A ubiquitously expressed transcription factor, specificity protein 1 (Sp1), interacts with the amyloid precursor protein (APP) promoter and likely mediates APP expression. Promoter-interaction strengths variably regulate the level of APP expression. Here, we examined the interactions of finger 3 of Sp1 (Sp1-f3) with a DNA fragment containing the APP promoter in different ionic solutions using atomic force microscope (AFM) spectroscopy. Sp1-f3 molecules immobilized on an Si substrate were bound to the APP promoter, which was linked to the AFM tips via covalent bonds. The interactions were strongly influenced by Pb 2+ , considering that substituting Zn 2+ with Pb 2+ increased the binding affinity of Sp1 for the APP promoter. The results revealed that the enhanced interaction force facilitated APP expression and that APP overexpression could confer a high-risk for disease incidence. An increased interaction force between Sp1-f3 and the APP promoter in Pb 2+ solutions was consistent with a lower binding free energy, as determined by computer-assisted analysis. The impact of Pb 2+ on cell morphology and related mechanical properties were also detected by AFM. The overexpression of APP caused by the enhanced interaction force triggered actin reorganization and further resulted in an increased Young's modulus and viscosity. The correlation with single-force measurements revealed that altered cellular activities could result from alternation of Sp1-APP promoter interaction. Our AFM findings offer a new approach in understanding Pb 2+ associated neurodegeneration., Competing Interests: Declaration of competing interest The authors report no declarations of interest., (Copyright © 2020. Published by Elsevier Inc.)

Owing to its electronic conductivity and electrochemical reactivity, polyaniline (PANI) can serve as the cathode for rechargeable zinc-ion batteries (ZIBs). However, it suffers from fast deactivation and thus performance deterioration because of spontaneous deprotonation during charge/discharge. Here, we report an effective strategy to improve the electrochemical reactivity and stability of the PANI-based cathode by constructing a π-electron conjugated system between PANI and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) on carbon nanotubes (CNTs). The impressive performance of the post-treated CNTs-PANI-PEDOT:PSS (t-CNTs-PA-PE) cathode is largely attributed to the -SO 3 - H + groups in PSS, which acts as an internal proton reservoir and provides enough H + for PANI's protonation, thus promoting its electrochemical activity and reversibility. Besides, the strong interactions between PANI and PEDOT:PSS assist the stretching of π-π conjugation chains, bringing about enhanced electronic conductivity. Consequently, the t-CNTs-PA-PE cathode achieves a high capacity of 238 mA h g -1 , together with good rate capability and long-term stability (over 1500 cycles with 100% Coulombic efficiency). Through exerting the freestanding t-CNTs-PA-PE, a flexible ZIB was further constructed with both outstanding electrochemical properties and superior high safety. This work demonstrates the availability of conducting polymer cathodes for high-performance ZIBs, fulfilling the need of flexible electronics.

A DNA tetrahedron as the most classical and simplest three-dimensional DNA nanostructure has been widely utilized in biomedicine and biosensing. However, the existing assembly approaches usually require harsh thermal annealing conditions, involve the formation of unwanted by-products, and have poor size control. Herein, a facile strategy to fabricate a discrete DNA tetrahedron as a single, thermodynamically stable product in a quantitative yield at room temperature is reported. This system does not require a DNA trigger or thermal annealing treatment to initiate self-assembly. This DNA tetrahedron was made of three chemically ligated triangular-shaped DNAs in unconventional ladder-like arrangements, with measured heights of ∼4.16 ± 0.04 nm, showing extra protections for enzymatic degradation in biological environment. They show substantial cellular uptake in different cell lines via temperature, energy-dependent and clathrin-mediated endocytosis pathways. These characteristics allow our DNA tetrahedron to be used as vehicles for the delivery of very small and temperature-sensitive cargos. This novel assembly strategy developed for DNA tetrahedra could potentially be extended to other highly complex polyhedra; this indicated its generalizability., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We have developed a reversible photoswitching platform based on 3D DNA nanotubes by integrating photoisomerizable azobenzene molecules along the edges. This would allow the reversible conformational changes of the nanotubes between linear and bent features and the switchable patterning of gold nanoparticles in response to UV/Vis irradiation. This work provides a new strategy to create reversibly reconfigurable transformative nanomaterials for potential applications in the fields of renewable energy, sensing, nanorobotics and nanomedicine.

This study reports biosensing using graphene field-effect transistors with the aid of pyrene-tagged DNA aptamers, which exhibit excellent selectivity, affinity, and stability for Escherichia coli (E. coli) detection. The aptamer is employed as the sensing probe due to its advantages such as high stability and high affinity toward small molecules and even whole cells. The change of the carrier density in the probe-modified graphene due to the attachment of E. coli is discussed theoretically for the first time and also verified experimentally. The conformational change of the aptamer due to the binding of E. coli brings the negatively charged E. coli close to the graphene surface, increasing the hole carrier density efficiently in graphene and achieving electrical detection. The binding of negatively charged E. coli induces holes in graphene, which are pumped into the graphene channel from the contact electrodes. The carrier mobility, which correlates the gate voltage to the electrical signal of the APG-FETs, is analyzed and optimized here. The excellent sensing performance such as low detection limit, high sensitivity, outstanding selectivity and stability of the graphene biosensor for E. coli detection paves the way to develop graphene biosensors for bacterial detection., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Stimuli-responsive DNA-based materials represent a major class of remarkable functional nanomaterials for nano-biotechnological applications. In this review, recent progress in the development of stimuli-responsive systems based on self-assembled DNA nanostructures is introduced and classified. Representative examples are presented in terms of their design, working principles and mechanisms to trigger the response of the stimuli-responsive DNA system upon expose to a large variety of stimuli including pH, metal ions, oligonucleotides, small molecules, enzymes, heat, and light. Substantial in vitro studies have clearly revealed the advantages of the use of stimuli-responsive DNA nanomaterials in different biomedical applications, particularly for biosensing, drug delivery, therapy and diagnostic purposes in addition to bio-computing. Some of the challenges faced and suggestions for further development are also highlighted., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We develop a versatile recognition system based on 3D triangular-shaped DNA nanotubes by integrating three different aptamer sequences along the three edges. This would allow multiple binding activities to be combined into a single system. The versatility of this nanotube platform can also provide a framework for spatial orientation and positioning of different aptamer-binding ligands in a 'pea-pod' architecture.

The first example of mitochondrial delivery of the anticancer drug doxorubicin (Dox) is presented by lipid-functionalized DNA nanocages (LNCs). Dox localized in mitochondria induces significant cytotoxicity and cellular apoptosis in MCF-7 compared with Dox localized in lysosomes. These results suggest that LNC has the potential to be an outstanding tool in the treatment of specific organelle-related diseases such as cancers., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We demonstrate the use of two different wavelength ranges of excitation light as inputs to remotely trigger the responses of the self-assembled DNA devices (D-OR). As an important feature of this device, the dependence of the readout fluorescent signals on the two external inputs, UV excitation for 1 min and/or near infrared irradiation (NIR) at 800 nm fs laser pulses, can mimic function of signal communication in OR logic gates. Their operations could be reset easily to its initial state. Furthermore, these DNA devices exhibit efficient cellular uptake, low cytotoxicity, and high bio-stability in different cell lines. They are considered as the first example of a photo-responsive DNA logic gate system, as well as a biocompatible, multi-wavelength excited system in response to UV and NIR. This is an important step to explore the concept of photo-responsive DNA-based systems as versatile tools in DNA computing, display devices, optical communication, and biology., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two-photon-regulated, shape-changing DNA nanostructures are demonstrated by integrating a DNA nanotube with a two-photon photocleavable module that enables the opening of the cavities of tube, and becomes partially single-stranded in response to two-photon excitation under 800 nm fs laser pulses., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)